A-Z of syndromes - Down’s syndrome
Down's syndrome is a genetic disorder and is one of the most common congenital anomalies, affecting 1:1000 infants in the UK
Down's syndrome is a genetic disorder and is one of the most common congenital anomalies, affecting 1:1000 infants in the UK. The syndrome occurs in all races and males and females are equally affected. It was named after a British doctor who is credited as the first person to describe the condition.
Down's syndrome is caused by an extra chromosome, or part of an extra chromosome. When the chromosomes are mapped out in pairs the extra genetic material is located on the 21st set of chromosomes. This is also known as trisomy 21.
This extra genetic material is caused by a failure of chromosomal separation during spermatogenesis, which is rare, or preparation of the ovum.
It is associated with advancing maternal age. Another less common mechanism of transmission is when there is a new mutation in one of the parents who is unaffected but has the potential to pass the mutation with the extra genetic material on to their children.
There is no one typical presentation of the condition. In common with other syndromes there is a trajectory of severity, ranging from individuals who are mildly affected to those who are severely affected, and there is often a shorter life expectancy.
Down's syndrome characteristics
Infants with Down’s syndrome have a characteristically wide face with slanted eyes caused by epicanthic folds, an underdeveloped lower jaw, a flat bridge to the nose and a small mouth giving the impression of an abnormally large tongue.
The head appears flattened and there is a short neck with spare skin. There is often a single palmar and plantar crease, usually a wide space between the first and second toes.
They may also have hypotonia and as these children grow they do so more slowly than their peers and have short stature.
The syndrome also has an association with congenital cardiac defects and gastrointestinal atresia, and individuals are more prone to infections because of an impaired immune system
Although many children with the syndrome cope well in mainstream schools they can also have mild to moderate learning difficulties.
This condition can be identified before birth during routine antenatal screening where an ultrasound may indicate increased nuchal fold thickness or a cardiac defect requiring further investigation. There is also a blood test which identifies specific markers.
To confirm the diagnosis, a chorionic villus sample or an amniocentesis sample can be obtained and the infant's genetic profile confirmed. After birth a diagnosis can be confirmed by genetic profiling.
The implications of the syndrome for children’s nurses depend on the child and family's reason to access healthcare. Children may present for immunisations, management of obesity, for support during an acute healthcare crisis such as chest infection or have a requirement for repeated corrective surgery.
Consistent with the philosophy of nursing children, individuals with Down’s syndrome should have individualised nursing care plans framed with a family-centred care ethos to meet their needs.
Aden and Adam are 5-year-old twins with Down’s syndrome. They are prone to ear infections and chesty coughs but are otherwise bright and happy children who cope well in a mainstream school.
Aden became listless, seemed to have a fever and lost his appetite. He was diagnosed with an ear infection and given antibiotic syrup but this did not seem to have the desired effect and, following a second course of antibiotics, the GP took a blood sample.
The results were abnormal and the GP asked the family to take Aden to a local hospital assessment unit. He did not mention his suspicion that there was a possibility of acute myeloid leukaemia.
At the hospital, the consultant repeated the blood tests and performed a thorough examination. He noticed unusual bruising and a lump in Aden’s groin. He mentioned the possibility of acute myeloid leukaemia to Aden’s mother who became distressed and a play therapist took the boys away so she could regain composure and inform the twins' father.
The diagnosis was confirmed after a bone marrow aspiration and a plan was made to transfer the family to the regional oncology service for further management. The need for chemotherapy was explained to the parents and they were reassured that they would be able to stay together during treatment. The plan included a routine screening for Adam as there was a 20-25% chance that he could develop the condition as well.
Throughout this difficult day the family had the support of an experienced staff nurse and a nursing student.
- Wu J, Morris J (2013) The population prevalence of Down’s syndrome in England and Wales. European Journal of Human Genetics. 21, 9,1033-1034.
- NHS Choices
- Contact a Family
Doreen Crawford is nurse advisor at an independent health consultancy and Annette Dearmun is divisional head of governance and nursing (children and women’s division), Oxford University Hospitals NHS Trust. Both are consultant editors, Nursing Children and Young People.